Oral-History:John M. Reid

About John M. Reid

John Reid worked as a Navy electronics technician (1944-46), then went to the University of Minnesota for his Bachelors in Engineering (1950). He went to work in John Wild’s laboratory, doing much of the actual technical work of building his ultrasound machine and adding imaging capabilities. He received his Masters at Minnesota, then moved to the University of Pennsylvania in 1957 for a doctoral program. He received his PhD in 1965, his graduate work consisting of adapting an ultrasound machine to look at the heart (electrocardiography), working under Herman Schwan, with Calvin Kay and Claude Joyner. He then moved to Seattle, working at the University of Washington and the Providence Hospital. His research focused on the use of pulse Doppler imaging on blood flow, and the use of pulse Doppler/CW Doppler for vascular diagnois. He then moved to Drexel University, where has undertaken research in a wide variety of fields.

About the Interview

JOHN M. REID: An Interview Conducted by Frederik Nebeker, IEEE History Center, 6 October 1999

Interview # 367 for the IEEE History Center, The Institute of Electrical and Electronics Engineering, Inc., and Rutgers, The State University of New Jersey

Copyright Statement

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Request for permission to quote for publication should be addressed to the IEEE History Center Oral History Program, Rutgers - the State University, 39 Union Street, New Brunswick, NJ 08901-8538 USA. It should include identification of the specific passages to be quoted, anticipated use of the passages, and identification of the user.

It is recommended that this oral history be cited as follows:John Reid, an oral history conducted in 1999 by Frederick Nebeker, IEEE History Center, Rutgers University, New Brunswick, NJ, USA.

Interview

Childhood, family, and educational background

Nebeker:Could we begin with where and when you were born and a little about your family?

Reid:I was born in Minneapolis in 1926.

Nebeker:What about your family?

Reid:My dad was in real estate and my mother did not work. I have a brother who is reviewing oral history for a managers’ association, and a sister who runs a printing business. They are both in Minneapolis and both younger.

Nebeker:Were you always interested in science and technology?

Reid:Yes, pretty much so. I was sort of underweight and skinny and did not have much coordination, so I was a miserable participant in sports.

Nebeker:So it was a second choice?

Reid:No. The reason was interesting. I remember Dad bringing the first battery radio into the house. He found all kinds of things in houses that were for sale that people had left. We got things like a piano. We had the battery radio to listen to Joe Penner, Fibber McGee, and Molly on Sunday nights. Later, looking in at those vacuum tubes and watching the colors flicker back and forth, I started to wonder how people could make anything that complicated and how it works.

Nebeker:Wasn’t that great to be able to see the tubes?

Reid:Yes.

Nebeker:Did you get interested in radio as a hobby at all?

Reid:I did, but I was not able to do much about it because it cost money and there was not a lot of that around during the Depression. I remember in the ninth grade borrowing a radio amateur’s handbook from the science teacher and I managed to wade through most of the first chapter. I did discover something about how a tuned circuit worked in that class later on.

Nebeker:You were a boy when World War II came along, is that right?

Reid:Yes. I think what really set me was in the eight grade when they handed out a block of wood and a ruler and told us to use the scale and draw where the water line would be when you put the block of wood in the aquarium. I was the only person in the class that came right on it. I figured that was really easy. I graduated from high school in 1944. I was 12 when I really became aware of the war.

Nebeker:Did you go straight on to the University of Minnesota?

Reid:No. I went straight in the Navy after a summer. I was pretty near-sighted at the time and I did not meet the regular Navy requirements. I could not enlist. I was drafted in the fall of 1944. To stay out of the infantry, I had heard about the EDDY test. That was the test they used to select radio and radar technicians. I had heard about Captain Eddy, the navy officer who built a hearing aid into his pipe so he could stay on active duty. The other hearing aids were rather large and bulky in those days; this way he could conceal it. When they discovered it, instead of cashiering him, they put him in charge of a program to train the technicians because the navy was terribly short of maintenance people. Radars were just being installed on ships and they had direction finders and sonars, as well as standard radio.

Nebeker:There was a fantastic development of electronics in that war.

Reid:They needed people out on the ships who could handle them.

Nebeker:So you took the Eddy Test?

Reid:I took the test and passed it, and when they would not let me enlist they said, “Take this letter with you when you get drafted and show it to them.” That is exactly what happened. On my way into the interview for selection, I handed it to the chief standing at the door. He took one look at it and said, “Okay, go back there and sit down. You are in the Navy.”

Nebeker:How did that go?

Reid:That was very interesting because I learned a lot of practical electronics in a very hands-on way.

Nebeker:What sort of systems were you working with?

Reid:The school went through everything. We had elementary electricity in Michigan City, Indiana, and then we went down to Oklahoma A & M, which was a contract school—the first Navy base where people were leaning out of the windows saying, “You will be glad” rather than “you’ll be sorry.” There were about three girls on campus for every guy. I remember coming on leave from that and the family radio had stopped working. I knew enough about quick testing with a screwdriver to find the stage that was out and then just use a simple spark test to find the shorted capacitor and replace it.

Nebeker:The family, I hope, was impressed.

Reid:Yes, they were. My total testing kit was a screwdriver and a soldering iron. Then the final radio, radar and sonar were at Navy Pier in Chicago. It was a big program. The Navy Air Force was down in Texas. There was another school somewhere else. Since I lived in Minneapolis, I figured I could go home once a month and take a lot of my laundry with me.

Nebeker:How long did all this training take?

Reid:It took about a year. Roosevelt died when we were at Oklahoma A & M, and the newsboy came in announcing that the Germans surrendered, too. They were close together. We just told them to get out of there, that nobody was interested in taking off to celebrate the Germans surrendering because we long ago decided that they had nothing to do with us. When I was at Navy Pier, the atomic bomb went off and there was a big celebration and people left the base.

Nebeker:Are you one of these who can remember what you were doing when you heard that report?

Reid:Vaguely. We were on the pier. It was like one great, big, long hall with bunks and classrooms. That is where I was.

Nebeker:I take it you enjoyed that training?

Reid:Yes. I can remember Pearl Harbor and where I was. I was reading a book on the defense of America and how we were in bad shape.

Nebeker:That was Sunday morning?

Reid:Yes. Everybody else had gone to church and I was sitting there reading a book by George Fielding Elliott. I didn’t turn on the radio until I was told of the attack.

Nebeker:What happened with your Navy career?

Reid:Because of my eyesight, I could not be assigned to a smaller ship than a light cruiser, so I applied to stay on as an instructor. I think they figured I was not aggressive enough. I had the highest score of anybody who went out to the fleet. I was sent to New York during the Christmas vacation traffic rush in 1945. People were coming home and going out to meet their relatives. The whole train system was just about broken down. We had a mixture of coaches from different lines. The heating did not work and it took twenty-four hours to go from Chicago to New York. I finally found the armed guard center and got on a ship that immediately went into dry dock in the Brooklyn Navy Yard.

Nebeker:Is the ship manned at that point?

Reid:Yes. It had been in the Pacific and they had brought it back through the Canal. Our assignment was to take all the Navy college program graduates. They had V-5 and V-12 programs, and one was for pilots. Our job was to convince them that they should sign over into the regular Navy. People were getting discharged on points and ships were getting stuck with insufficient crews to move. They were trying to bring people home and they needed an officer. We got into that state, but they had so many ensigns on board that they finally organized them into work parties. Our division had five ensigns to help scrape solder off the decks after me.

Nebeker:Were you an ensign?

Reid:No, I was an electronics technician. I had made second class by the time I graduated. We started out being called RTs for radio technicians. They broadened it to ETM for electronics technicians mate.

Nebeker:Were you working on particular equipment on the…?

Reid:Yes. I had the surface search radar built by the Raytheon Corporation. The receiver’s serial numbers were three and four. That was a lot of fun because we went out and did target practice.

Nebeker:It wasn’t in dry dock very long?

Reid:No. We were just outfitted and they upgraded a few things, then we went out on this cruise with all these new ensigns. A couple of the engineering graduates came up to the radar shack and volunteered to help. They just wanted to see the equipment. Our main occupation of the evening was playing bridge anyway, so they fit right in. It was pretty nice.

Nebeker:How long did you do that?

Reid:We cruised to Bermuda and went up to Quebec until the summer of 1945. I was in the Navy for one year, ten months, and three days.

Nebeker:The summer of 1946 probably?

Reid:Yes.

Nebeker:Were you discharged then?

Reid:Almost. I should have gotten out in June or July but our ensign, without telling me, had requested that I stay on because they were supposed to mothball the equipment. We went into the Philadelphia Navy Yard. That was when I discovered what Philadelphia summers were like. I vowed I would never return. I had done a correspondence course in college algebra while I was on the ship. When I went back to Minnesota, I went into the engineering program right off the bat.

Nebeker:You got a Bachelor in Engineering in Minnesota?

Reid:Yes. I worked as a technician on their linear accelerator project. I had a little experience there. A couple of my friends and I even started a small radio repair business on the side. I guess that is before the linear accelerators were really going.

Nebeker:While you were a student there you worked on linear accelerators?

Reid:Yes.

Nebeker:Was your Navy training a help to you in getting into the EE program?

Reid:Yes. I remember in some of the labs, if there was an odd number of people, I would always insist on being the one who worked alone because I could do the lab in half the time.

Nebeker:What was your plan at that point?

Reid:I really had not had any real goals set up. I knew I wanted to be an engineer and I wanted to work in the field. There were developments like the distributed amplifier that removed the gain-bandwidth limitation on vacuum tubes, and point contact transistors had come along. I knew things were going to be happening. When I got out of school about the only jobs that were available were with the missile contractors on the West Coast.

Nebeker:That was in 1950 that you received your Bachelor’s Degree?

Reid:Yes. I really did not want to move to the West Coast and I did not have any particular desire to work on missiles. I stayed with the linear accelerator project for a couple of months, as a junior engineer doing the same thing, but the title was different. That was the point where John Wild, who had gotten an NIH grant for ultrasound, went into the department chairman and asked if they had a student who would work with them. They figured that I was the most disposable of the group.

Nebeker:You were not planning at that point to do graduate work?

Reid:No. Well, there was something going on there because I realized that it was only at the very end of my senior year that I got into anything that I found really interesting. We did solutions for the parallel plane wave guide. I could see that this was the basis of how wave guides worked but they were not parallel plane. I had bolted together a bunch of ten centimeter wave guide sections and lit bulbs and microwaves and that sort of thing. I knew some of the basic physics just by experiment and I figured there was a lot more. We had just been introduced to Maxwell’s equations in our last semester with a very fast mention of the Fourier expansion series, and no transient analysis. I had been working with pulse radar and I knew something about that.

Nebeker:Was Wild at the University Hospital?

Reid:Yes. He was a fellow in the surgery department, and had come from England. He had developed a gastrointestinal tube that they used on the victims of the bombing that distended and blew up because of pressure. The tube could be used to relieve that.

Nebeker:I see. He was an M.D., is that right?

Reid:Yes. He was a frustrated mechanical engineer in love with the steam engines whose family would not let him become an engineer because it was not socially acceptable. He took medicine, but he did not lose his interest. He had his own lathe in the basement.

Nebeker:So he was very accomplished mechanically?

Reid:Yes. He made a steam-powered outboard motor which we tested on some of the lakes around St. Paul.

Nebeker:How much did he know about electricity and electronics?

Reid:Very little. He was sort of an intuitive engineer.

Nebeker:It sounds like he was an engineer type?

Reid:Yes. He had made these catheters himself. He wound one that would do the breast stroke as it went down the intestine. He wound up filaments, wires, and springs and dipped them in latex rubber and built the whole thing himself.

Nebeker:His inclination was to work on that type of medical problem, something that an engineering device could help in some way?

Reid:Yes. He was interested in helping people, really. That was the basic idea. He found himself in the military hospital in London during the blitz and bombing and felt that these civilians were the ones who needed the help. The military doctors did not have a lot to do, so he worked at some of the civilian hospitals and saw the problems caused by distension. If you have a little bit and the surgeon goes in and irritates the bowel more, then you get a lot more distension. He was trying to find some way of keeping the surgeons away from the patients. That is when he came up with a tube and made it work. Whereas an American tube along the same idea did not work, but it was patented in the States, which got him into all kinds of trouble later. In the main course of what I was working on, one of the earlier surgical specimens that he got from a patient that he had used the tube on turned out to contain cancer. He had heard about ultrasound at a party with a fellow named Finn Larsen, who was one of our Assistant Secretaries of Defense after this period. He was the Director of Research for Minneapolis Honeywell. Finn told him about the echo ranging radar simulator that Bausch & Lomb had developed for the Navy. They had installed one out at the Wold-Chamberlain Air Base in Minneapolis. A friend of mine from my high school days was the First Class technician who had installed it. That all developed later. Wild took his sample out there and hung it over the edge of this water tank. The radar simulator flew an ultrasound transducer with the same beam patterns scaled down as a radar. I take it you have not heard of this device?

Nebeker:No, I do not know about this device.

Reid:The basic problem we had in World War II was that nobody had ever flown a radar set over the islands of Japan, the South Pacific, or Germany for that matter. We did not know what they were going to look like. How do you teach a bombardier how to hit a particular target when you get this picture? I discovered later in the Navy that a navigator would bring down a road map and stand in front of the radar indicator and ask me, “Is this that? Where are we?”

Nebeker:The Navy built this with a model?

Reid:Yes. Everything was slowed down. The ranging time for sound in water is around twelve micro-seconds per centimeter and for radar it is about fifteen micro-seconds per nautical mile. They converted nautical miles to centimeters and they could model it. They built up a relief map on the bottom of the tank. They did a lot of experiments on islands we could fly over to find out how to build the relief. They exaggerated the vertical profile of that and used carborundum powder for the cities to get the entire reflection. They discovered that if you shook salt into the water it looked like a rainstorm. This whole thing was integrated to hook onto an APS 15 aircraft bombing radar. The controls worked just like the navigators were in an airplane. They could even practice dropping bombs and it would mark the charts that were laid out on top of the tank apparatus where the bombs would have hit.

Nebeker:Was this completed and used during the war?

Reid:Yes. Well, the installation at Wold-Chamberlain came after the war. I do not know about the other installations. I think the development was done during the war.

Nebeker:Wild knew about this device and thought he could get some…

Reid:Yes. Finn Larsen directed him, and Larsen had directed the development of this device or at least worked on it. He sent Wild out there and Wild brought a bowel cancer specimen along and found he could see the infiltrating edge of the cancer on the A scope picture before the thickening had changed. His original idea was to measure the thickness of the bowel wall, because he felt that it would change depending on the cause of the blockage. He was trying to determine which blockages could be relieved by the tube and which required surgery. Once he found that he could see the cancer early on, he thought this might really be something.

Nebeker:That is when he applied for the NIH grant?

Reid:No. He got some preliminary data. Don Neil is my friend and the guy that had installed this. He built Wild a little chamber that would hold one of the transducers. This was a fifteen megahertz X-cut quartz airbacked transducer. It had a little water column in it, and they sealed it with a piece of condom rubber over the end. So, Wild had a portable probe that he could put on people. He brought a couple of women with breast cancer out to the air base from the University Hospital and found that he could see a difference, again just using the A scope. That is a much higher frequency than they use today because the penetration was not all that good. Since the scattering is stronger at higher frequencies, we did not have any trouble with depth. He would sometimes have to push on the tissue when he got a woman with very large fatty breasts. Specificity was very good. Then he got the NIH grant.

Nebeker:That was specifically to develop this ultrasound imaging?

Reid:Yes.

Nebeker:Or detection? Was is thought that one would actually get images?

Reid:No. Not at that time, that came later. We just used the A scope and tried to look for some measure. Finally, the area under the curve turned out to be the best diagnostic indicator, but to account for attenuation we had to take a normal sample from the other breast in the same location and adjust the gain, and we had time varied gain. I had to build that into the equipment.

Nebeker:To get the chronology, you graduated in 1950?

Reid:Yes.

Nebeker:How soon did you start working for Wild?

Reid:It was that fall. We had something running by January of 1951. I remember we were not getting many echoes, so we asked Finn if he would come out and take a look at what I had built. Or at least Wild asked him.

Nebeker:This was no longer at Wold-Chamberlain?

Reid:This was in Wild’s basement. Apparently according to the story he told me, the head of the surgery department was Owen Wangenstein, and he was very famous in surgery circles and a great cutter and hacker and the butt of many medical student jokes and faculty roasts. He told Wild in the elevator one day that he had to give up his British patent. Wild was trying to get the British patent transferred to be a reciprocal patent in the United States. He had come into interference with a counter patent from the guy who had developed the tube which did not work very well. The medical establishment at that time had a very patrician attitude that the patents and commerce were too beneath the doctors to get their hands dirty with monies. He had to give up the patent. The British changed their tune when the Americans got all the patents on how to manufacture penicillin, although it was a British discovery. The British had to pay to even make penicillin.

Nebeker:As an employee of the University of Minnesota Hospital, it was thought that Wild should not be doing that?

Reid:Yes. He just demanded that Wild hand it over. Wild owed his lawyers some money and his lawyers had signed over the interest on the patent. It was not his to give away. He was on the outs. I’m not sure exactly what they did except that he had no laboratory space. They were still doing the administration of his grant and he was drawing a salary. We had to build our lab in his basement. Our first job was to build workbenches, and he brought in a little wooden stove since there was no heat in the basement. He had his lathe there.

Nebeker:Can you tell me about this first ultrasound system that you built in his basement? What it was, the design of it, and what equipment you were able to use?

Reid:The biggest help in the design was the Radiation Laboratory series of books on radars because the circuits were very close. I had already gone through the sonar classes and had kept my Navy notebooks and knew that was an entirely different kettle of fish. I had some guidance there. I bought a big power supply figuring that I would have to power Lord-knows-what by the time we got it running. I had 300 volts at 1-2 amps, I think. I built a calibrated attenuator by using DC measurements in the electrical engineering building, filing the carbon resistors to value. The signal generator I already owned because of the radio repair business, so I brought that along, and then my tube tester. I decided to see what I could use in surplus. I found a 60 megahertz IF strip complete, which looked like a good place to start. I would have to run an oscillator at 45 to beat the 15 up to 60, which was sort of backwards for most equipment in those days. They very seldom went to a higher frequency. I was a little unsure about designing an oscillator because we did not go into that, but I found the instruction books for the Hewlett Packard equipment that we had in the linear accelerator project. I copied down an oscillator using a triode, and that’s what I built.

Nebeker:You built that oscillator?

Reid:Yes. Since we wanted gated bursts of sine waves, I just used a range mark generator circuit to get that and then amplified it to a wide band amplifier. This is a very inefficient X-cut quartz transducer, and they had a fairly high drive voltage on it in the Navy equipment. I had that as a guide. The radar simulator ended with everything that was connected to the radar sets. There was no receiver in there. The transmitter was pretty straightforward. I changed to a 3E29 and got a variable 3,000 volts supply as the plate supply. I think the original is a 1,000. I thought we might need more output. I just had to figure that we would undoubtedly have to change something as we went along—I made sure we had the capability to do it. It was like building a ham transmitter. That was something I had wanted to do for a long time. I got it all together and it seemed to work okay on test targets, but we were not getting many tissue echoes. That is when we asked Finn if he would come out and take a look at it, or when Wild asked him. He could not make it, but he sent the head of Honeywell’s aeronautical research, Hugo Shuck. He is the University of Pennsylvania graduate who did a variable frequency tuning fork. He has some sonar patents, the bearing deviation indicator, and some other ones. He said, “You just do not have enough gain. There is plenty of noise and grass on the scope, but you have to get more gain.” That meant the only way I could do it with that setup was to narrow the bandwidth to do a bandwidth-gain tradeoff. It got to the point where I was getting a feedback on the shell of the low-level tube because it was grounded through a pin, which was a fairly long connection. It was not a ground connection, so I had to build a screen around my earliest amplifying tube. I had to put partitions in the IF strip to stop the wave guide feedback. Again, this was all mentioned somewhere in the Rad Lab books. The only problem I had was that Wild figured I was not working when I was reading a book.

Nebeker:You were working full time?

Reid:Yes. I had also gotten married and had a son at this point. I started doing a lot of work at home because the reading was easier to do there. I was an armchair amateur. I had never built anything from scratch.

Nebeker:What then?

Reid:One thing that impressed John was when he brought in a cube of beef and said, “Let’s see if we can get echoes.” He sat it on the transducer and there were a few little echoes at the start, but not much. I looked at it and said, “All the muscle bundles are going this [indicating longitudinally with his hands] way.” I turned it 90 degrees and we were going crossways, and the screen was suddenly filled with echoes. It was wonderful. He thought that was a wonderful discovery, the anisotropy of reflections from skeletal muscles. He quickly ground it up and we got an intermediate picture from the grinding. That is the sort of intuitive thing that was going on a lot in those days. Then we needed to use the machine on patients. Given his relations with the surgery department that was going to be difficult, except Wild always had this ability to talk to the low-level people as friends. A lot of the stuff that he used to build later equipment was just given to him. If he was going to go to a company he would go to the loading dock and talk to the guys there and work his way in. He went to the telephone receptionist for the surgery department. If anybody was scheduled for breast cancer surgery, she would call him the next day and give him the patient data. Without Wangenstein knowing anything about it, we could tell when the patients were coming through. One of his friends was the head of the obstetrics department. He delivered my son and daughter! He gave us some space at the back of one of the OB classrooms. We built the machine on a rolling cart and had a Tektronix oscilloscope for the A scope, and a regular film camera. We would keep it in the back of the classroom. The people usually checked in at night because they wanted them there early morning so they could do a few tests. We would just go down and grab a wheelchair from somewhere and bring the patient up. We would examine them in the back of the classroom, get the images and take the pictures. It was a view camera that had 4 x 5 cut film. He felt this was the most flexible kind of camera you could get. He had mounted it onto the Tektronix scope that we used for display. Then we would go back to his house and I would go into his front hall closet and we would open the film cassettes and put the film into the cut film holders and processing tank. Then the next day we would look at them and try to figure out what it was. I was the technician. I had belonged to a camera club at school and processed hundreds of negatives for my parents. They kept their whole collection of negatives in a shoe box and I made photo albums for the whole family, so I had done a lot of fast processing.

Nebeker:What was the success of that?

Reid:It took a couple of years to get enough patients to be certain of anything. It worked very well. We missed only one cancer. There was a picture of us using the equipment on the front cover of Electronics Magazine, the second reference to electronics, Number Six on my CV.

Nebeker:You published an article as early as 1952?

Reid:Yes. The Number Two (in the list of references) came first, the Science one. Wild had done some studies with Don Neal and with French. I forget French’s position, but he had to go first on the paper even though Wild wrote it. It was the medical tradition in those days.

Once I was back at the linear accelerator lab where I had a bunch of friends working, one of them said, “Why don’t you make images? Why don’t you scan the pictures?” I said, “We need some position data transmission system. We need sweep resolvers or sine/co-sine potentiometers.” My friend at the lab said, “No you don’t. If you keep your angles small the sine is approximately the angle and the cosine is about one. You can use linear potentiometers and make an image.” I thought about it, and went back and told Wild, “Let’s make images.” We had the signals and the video coming out of the machine since I had detected the RF, and he said, “Oh Jack, that is getting so complicated. Things in medicine have to be as simple as a paperclip or a hairpin. If it gets more complicated then that, nobody will use it.” I said, “John, it is already pretty complicated. I don’t think it will take a lot more.” He wanted to know what more it would take, and that is what hooked him. I said, “We need a motor to drive this thing back and forth—a variable speed.” He said, “I have this wonderful variable speed drive, based on overdriven clutches. It turns out he had been looking for a project to use this thing. The idea of hooking up a DC motor to it and running it really intrigued him. We had to make a mechanical linkage to run some dual potentiometers only for the sine, because the cosine was constant. The vertical coordinate was just the range sweep and the horizontal coordinate was the fraction of the range sweep picked off by a potentiometer. I had to build a little 12-volt DC power supply for one of the surplus motors we had. Incidentally, one of the first questions he asked me when I interviewed with him was would I be willing to steal to keep the project going? I explained to him that there was so much surplus material in the subbasement of the electrical engineering building that I was sure that it would never come down to that. He seemed to accept that and felt that I would be loyal enough. Those early Tektronix scopes had a plug arrangement at the rear that connected all the amplifiers to the deflection plates. All the inputs and outputs I needed were there. I just made a little box that plugged into the Tektronix scope and hooked up to his pots and the output of the range sweep of the video and we had an imaging system. That made the Publication in Science, Number Two on my CV. This was about six months ahead of the group in Colorado that had been, unbeknownst to us, working on the same idea. They had a much more complicated and elaborate set up. Holmes, the first author, was head of the department.

Nebeker:Was that Science article much noticed?

Reid:Yes. We had reprint requests from all over the world, and it is the basic reference that people use if they want to go back to the beginning.

Nebeker:At the time there was considerable interest?

Reid:Yes, up to a point. Radiologists considered that radiology was x-rays. It was not until they lost all the business in nuclear medicine that they realized that maybe they should broaden the field. It was just in time for the CAT scanners and MRIs.

Nebeker:In the medical profession there was not a great deal of interest immediately?

Reid:(Nodding “yes”) Wild was an odd character. He tended to get people’s complete support or complete animosity; there was very little middle ground. People used to say that “nobody else was imaging soft tissue, much less trying to differentiate cancer in the image from non-cancer.” It did not seem to be possible. “How were we doing it?” Using sound waves. Sound was something you used to talk with people on the telephone. “You guys are some kind of nuts. What kind of crazy idea is this?” After meeting Wild, they became firm in that conviction. One of the things that led me to leave was that people were starting to look at me a little funny, too. “How can you stand to work for that guy?”

Nebeker:How long did you work with Wild?

Reid:That is interesting. In 1957, I came to the University of Pennsylvania. I worked with him about six years.

Nebeker:You are listed as Research Fellow, Department of Electrical Engineering and Surgery, University of Minnesota, from 1950 to 1953. Then Chief Engineer, Medical Technological Research Development Department, in 1954.

Reid:Yes. We started in Wild’s basement and had the clinic in the back of the classroom. About this time, one of my friends had started talking to me about graduate school. Wild got a larger grant and switched to the Electrical Engineering Department at that point. Apparently they would not renew the grant through the medical school. He got a grant through Electrical Engineering. I was around EE a lot more. The people that I worked with before saw what I was doing, and one friend, Dick Evans, said, “Why don’t you register for graduate school?” I was doing what amounted to a very complicated thesis. Henry Hartig, the department head who started out as my advisor, said, “Well, that is all done. You cannot use anything that you have already done. You have to start now and do something new.” I did a study of how ultrasonic lenses focus in comparison to theory and did a master’s thesis.

Getting back to our support, we got a lab in the basement of the electrical engineering building, and that is when we built a real scanner—the one that goes back and forth, the rectilinear motion. I built up an intensity-modulated display that I could switch between this rectilinear sector scan and PPI. He wanted to build something that would go down into the bowel. He also did an oscillator that would scan the vagina, so I had to accommodate that. At one of the faculty things, perhaps a party, one of the medical school deans discovered that there was a medical project running in the engineering building. He felt that this was not allowed. That had to be in the medical school, and he made enough fuss with the administration that we were told we would have to move.

We had already made a connection at St. Barnabas hospital, downtown, where we had our clinic for examining patients, and he had talked to some of the doctors down there, including one I had known before. He had gotten us a room to use for the clinic. When we had to move, St. Barnabas, the grant sponsor, gave us the ground floor of an old house across the street. We moved the workbenches and made an examining room and our own dark room, and there was a real laboratory.

Nebeker:That was for three years, from 1954 to 1957?

Reid:Yes. We worked there until St. Barnabas got into difficulty. The university was sort of taking over the intern and residence programs of all the hospitals. St. Barnabas was using interns from South America whose English was very poor and their treatment of women was not what American women expected. To get interns they had to let Wild go. I left just before that.

Nebeker:This is the story of quite a few difficulties. How much of this was Wild’s personality, how much of it was unreceptiveness of the medical establishment?

Reid:I can’t separate them. All I knew was Wild’s side of things. None of the other people wanted to talk to me. I remember when I asked him some questions about cancer he said, “Why don’t you go look in the library?” St. Barnabas had a medical library. As it turned out, one of the doctors later complained that a non-physician was in the medical library and this was not supposed to happen. But I remember responding that I rode up and down on the elevators with doctors while they discussed the “liver in Room 304” and prospects of other patients. I figured if any lawyer wants to get information about malpractice suits, all he has to do is go to a hospital and ride up and down the elevators. They certainly do not have medical confidentiality.

Nebeker:How do you feel you are received as an engineer at these hospitals?

Reid:The young guys were wonderful. They asked questions and wanted to know how things worked. I was asked all kinds of things about electrocardiogram machines and diathermy machines and that sort of thing. But the older guys just kept their distance. There was a code when you were in a group of doctors and somebody came up and said, “This is Sam, I want you to meet Joe, (this meant that he was an M.D.) or this is Mr. Smith," (this meant that he is not an M.D.

Nebeker:It was very clear who the M.D.s were?

Reid:Yes. They used that code to separate this out. I think it is not as bad anymore. I certainly have lunch at the various hospitals I have been connected with, with groups of doctors, and they would swap stories. The psychiatrists had the best stories. Never by name, of course, but strange people.

Nebeker:Was there any other work with ultrasound going on in Minnesota?

Reid:Not in Minnesota. There was a George Moore at the surgery department, who was one of Wangenstein’s favorites, I was told. He happened to live only a few blocks from me and I knew his sister fairly well through our church. George had a grant to look at the brain, and he had a small lab. He was trying to build something to use ultrasound on the brain. Wild described it as an attempt to prove that what we were doing was impossible. He later did a Navy report to this effect. Ellen Koch references it in her thesis. George asked me about the power needed from the transmitter. He was about to wind coils out of quarter-inch copper tubing. He figured that if you needed peak power in the kilowatts you had to build a kilowatt transmitter. I told him no, you do not really have to. The average power is much lower. He wanted to know how I managed to see the echoes. His oscilloscope was an old Hewlett Packard low frequency device, and he was looking at the retrace to get enough speed to even see his transmitter pulse. I told him that there were better oscilloscopes out there and that you needed triggered sweep, fast sweep. He did a report that is mentioned in a thesis done by Ellen Koch, a historian at the University of Pennsylvania who worked on this booklet for the AIUM. Her thesis has a big chapter on Wild and me with all the references. She also did the Howry group out in Colorado and Bill Fry’s group in Illinois, who did not get into diagnostic ultrasound until somewhat later. He was working in surgery.

Nebeker:How did you come to make the move to Philadelphia, Pennsylvania?

Reid:Wild was going off in all directions, and he picked up a physicist who was a very abrasive fellow and hard to get along with. I was working nights doing my master’s thesis on focusing the ultrasound lenses. I had an optical system, a Schlieren system that showed the waves going through water so you could see the focus. I had to work at night, so I had to go to the electrical engineering department late enough that I could turn off the hallway lights and pull the shades down and stuff a blanket under the door. The other problem I had was security because they were convinced I had a girl in there. They would come in and look under all the benches and poke around. I told them, “Look, you can see what I am doing.” The same response as medical people: “Maybe what you say is right or maybe it isn’t, but I’d never heard anything like it before.” I was not showing up during the day. I told him I was working at night. Things were just getting to be so difficult. I told my wife, “It is time to do something else.” I needed to learn more.

The choices were either go on for more education, Ph.D. in engineering, or go to medical school and become an M.D. because those guys are at the top of the heap. She thought becoming an M.D. would be ridiculous because she would have to go back to work and we had two children by that time. I then sent out some letters to people I had met at meetings. We went to the meetings at the University of Illinois and the IRE meetings. I got some offers to go to Illinois, but they did not like some of my graduate school grades. I had tried to take advanced calculus and did not put the time in on it that I should have and I had some Ds there. They would not let me in their graduate program right away, but the University of Pennsylvania would. It was a probationary entrance. They had just seen a publication in the European journal Acoustica, on the use of ultrasound on the heart. They wanted somebody to build the machine. They wanted to build, buy, or borrow something that would get them into trying to look at the mitral valve.

Nebeker:Who in particular was that?

Reid:Herman Schwan was the laboratory director. Calvin Kay was the cardiologist, and he had two fellows that were interested. Claude Joyner was the one that stuck with the project the longest. I had some deep reservations because the heart was very difficult. You have lungs and ribs in there— at that time the access to the heart is only through a very narrow window. I was not at all sure things were going to work.

Nebeker:That was a project that Schwan or Kay decided should be done?

Reid:Together, yes. Herman had done a lot of work on propagation of ultrasound for therapy and heating and had a really good background in it. These people that were in the therapy science field were the only people I could go to for any kind of help or reference, the group at Illinois and Herman. Actually I was really impressed by Ed Carstensen, who is now retired from the University of Rochester. He had given a talk on the excess absorption due to the red cells in blood, relative motion absorption, which really impressed me with the methodology. Since he was working in Herman’s lab, I figured that was the best place to go. That was my second choice. When I got there, Carstensen had already left. He was working for the Army at the time down at Camp Detrick, the army's biological warfare facility that was closed later, in Maryland. The Moore school, Penn's EE Dept. where I was taking classes was building a new addition and we got a new lab over there. They had a lot of equipment left over from Carstensen’s days.

Nebeker:That was in the fall of 1957 that you came out here?

Reid:Yes.

Nebeker:How did your graduate program go here?

Reid:It was interesting because I had a lot of trouble with quantum mechanics. I think the first time I took it I failed it, as did every physics graduate student in the class. This caused a lot of rethinking on the part of the physics department. It was being taught by a graduate student and he would write out, “This is the wave function. Do you have any questions?” “No, no questions.” Then he would close the book and walk out. Every class was like that. He was running it like a quiz section. I retook it and managed to get through it, as did most of the other people. They let everybody redo it. I had Chinese circuit theory and met Salati, who developed the BMC connector, and it was a great experience. Instead of being alone in a basement or surrounded by a bunch of doctors, I had graduated into a group of engineering professors and other graduate students.

Nebeker:Did you think from the start that you would be working with Herman Schwan?

Reid:Yes. It was sort of parallel play more than working with him. He did not know the kind of equipment I was using. I had to build up a system. I had tried to see if we could use some of the commercial echo ranging things, but they were quite expensive and I could not get much technical detail. There were trade secrets on materials testing.

Nebeker:The stuff that was developed for materials testing?

Reid:Yes. We did get a transducer built by Curtis Wright that they used for immersion testing. It worked all right but it had very sharp edges, and this was the only housing that they had. If they wanted to assign engineers and do a special project, it would cost more money than our whole grant. I was actually on a salary through Herman’s ONR grant until we got a grant to work on the echocardiography. Originally there was not much and I had to scrounge stuff.

Nebeker:How did the echocardiography grant come about?

Reid:It was a regular NIH grant. Throughout this whole time NIH was developing its grant program. When we started out back in Minnesota, they were used to giving medical school professors $1,000 to cover glassware and somebody to wash it up at the end of the day. No salaries were ever put on NIH grants. Wild’s grant was regarded as outlandish, having a salary for an engineering student and a stipend for him and a lot of equipment. We wanted to get electronic stuff, and he was buying some microscopes so he could look at the tissues. It was a project that never really got started because of those political people, and I think still has some merit and somebody should be doing it.I remember the first time we had a site visit, it was the NIH staff member who was looking at the grant, Ralph Meader. He showed up and we explained everything and showed him the pictures. This was when we were in the basement of the Electrical Engineering building. He had brought some associate who only spoke German who had some knowledge of materials testing with ultrasound. The two of us could have communicated with a blackboard okay. He may have been a separate visit; I may be getting these two confused. When the NIH staffer left through the door, he turned around and said, “Well, thank you for showing me everything, Dr. Wild. I am certain that it is interesting, but I don’t believe a word of it,” and he left. John was paranoid enough without feeling that NIH was on his case. He did lose his grant in the middle of the grant year after I had left because he got into a fight with the people that were giving him the lab space and sponsorship. NIH took all the equipment back to Bethesda, and although one of the later guys saw it there in a subbasement, nobody was able to find it after that. He had rebuilt it a couple of times because his new ideas could never get done in time, so he wound up rebuilding my old machine.

Nebeker:In the University of Pennsylvania, from the beginning, it was your project to build this?

Reid:And to write the grants. Incidentally, we had another site visitor in Minnesota. They sent Ted Hueter, who did a book called “Sonics” and worked on medical ultrasound. He showed up as a one-man site visit the day we did the human brain at operation that was described in one of those Electronics magazine articles. He had to scrub and put on a white coat and came into the operating room. He saw what we were doing and he knew enough ultrasound to believe what we were doing, but it was still a very strange site visit to have an unannounced visitor. Now when you get a site visit, twenty people might show up. The arrangements go on for weeks in advance. The work at Penn really was my project. I worked on transducers using barium titanate.

Nebeker:You had to build the whole system yourself? You could not buy these things off the shelf?

Reid:Yes. Strangely enough, my memory of what that system was is rather dim. It burned up some time after I had left it, so there is nothing left of it. Again, I bought a big power supply. Transistors were around, but I felt they were pretty unreliable. I did not want to learn all about transistors at the time—we needed to get something running fast. I think I have the schematic for that machine somewhere. I hired an undergraduate to do a lot of the wiring and the punching, so it was relatively straightforward. I had some design problems because I was trying to build an arbitrarily wide band amplifier using some of the publications that had just come out on the IRE proceedings. I got into trouble because on the strong signals you would overload the stage, then the recovery transient would propagate through the system. Some of the poles that you had to put near the origin in the complex frequency plane to overcome the fact that there was a zero there had very low damping. So the transient behavior was terrible, I had to tear all those inter-stage things out and build an untuned amplifier that had limiters between stages. I found some oscilloscopes and a moving film scope that I could use. It is shown in one of these pictures. Here [pointing] is the moving film camera on the Fairchild scope on a spare cart that made a moving record. My switched attenuator for the receiver gain control, the transmitter, and the power supply is down here, and a lot of empty space.

Nebeker:You were working with Claude Joyner, is that right?

Reid:Yes. Once we got it in the shape where we could wheel it out—it was just this part with the electronic scope. We did not have the continuous film recorder until later. We went into the dog lab and we were trying to figure out where the echoes were coming from and which heart structures were we seeing. Dog hearts are smaller and they beat faster; it is really hard to see what is going on. I think that is why I found enough equipment to make the continuous film recorder so we could spread it out and take a look at it. At this point Dr. Edler, of Edler and Hertz published his Ph.D. medical thesis where he had pushed needles through the hearts of cadavers in the same direction that they put the sound beams during the exams. Edler proved that his diagnostic echo came from the leaflets of the mitral valve itself. The main idea then was to get this trace that was very different in mitral stenosis than in any other condition. A lot of times you can fix mitral stenosis by doing a closed heart operation. You did not have to hook the patient up to a heart-lung machine, which was much more risky. So they needed the ultrasound to select patients for operations. He had shown that the sound beam was going through a leaflet on the mitral valve. What they thought was a wall of the left atrium was really the mitral valve, and what we were seeing was the mitral valve motion. That suddenly made sense to everybody. A lot of mystery as to what these tracings meant was suddenly cleared up and he said, “We do not need to do anything in a dog lab. We need to go see patients.” We installed it in the cath lab.

Nebeker:What you were able to image there was the mitral valve?

Reid:Yes, the mitral valve. The study had other interesting things findings because the normal valve moved toward the chest wall twice in normal subjects except me. I am the only presumed normal that did not look normal on the echocardiograph. Through the ultrasound I know I have some liver cysts, gallstones, and a little thickening in one of my blood vessels. They do not know what to do about it if you do not have any symptoms. I remember presenting the two motion traces at a meeting where a listener got up and said, “That is crazy. The mitral valve opens at the P-wave when the atrium contracts and then it closes again. What do you mean it opens twice? That is ridiculous. You are doing something wrong. You do not know what you are doing.” Bob Rushmer from the University of Washington happened to be in the audience. He had gotten a hold of me the week after I arrived at Penn to ask me if I would move to the University of Washington. He had come through Wild’s lab and seen my thesis on focusing and decided that this was the sort of technical background his group needed. They were working on some ultrasound measuring devices. He said, “You are forgetting that there is a negative pressure in the chest and the heart is larger when it is in the chest. We see one peak of motion in dogs all the time. When you open the chest wall the heart shrinks. Once the mitral valve opens, it stays open because it is hitting the wall.” They put ultrasound transducers to measure diameter of the motion inside the heart, and as soon as the chest is sewn shut the negative pressure reestablishes itself and the heart gets larger. The papillary muscles tighten up and the motion changes—it opens twice, just as our records showed. That was very nice.

Nebeker:There were some other people looking at the heart?

Reid:The Swedish group had started earlier, and they had some support from Siemens who had adapted one of the regular little materials testing devices. The resolution was not very good. Gramiak followed us, but he got his 2-D system running and he used contrast materials to figure out the whole shebang--the anatomy, that is. We never did any successful two-dimensional imaging of the heart. We tried it with a manually operated scanner, but we could not clearly figure out what the pictures were showing.

Nebeker:What you were able to do was detect that motion?

Reid:Yes. The mitral valve, and we also swung around and saw the tricuspid valve and up to the aortic valve. We were doing a pretty complete survey of the heart, and it was valuable. We had to adapt it to record on the photographic record that they were buying for the catheterization lab. We were talking to the people at the company Electronics for Medicine up in New Jersey to adapt one of their channels to record our photographic tracers. Incidentally, the Swedish group was using an ink jet recorder that the Americans did not like because if you did not maintain it 100 percent of the time it would clog. As a result of this, Hertz had the basic patents on the ink jet recorder that is used today for computers. It is the only contribution that I know of where medical ultrasound fed something back into the engineering knowledge base.

Nebeker:That recorder was developed specifically for…?

Reid:For ultrasound, Hertz’ that is, the basic one he started with was just for electrocardiographs. Then he realized he had something that would really work fast. They had gotten it to the point where it would do colored pictures with a resolution of a 35 millimeter camera. In between, they were able to do computer printing of maps and comic strips and things like that. He got some prize from an information display society in New York in the interim.

Nebeker:What was the reaction to your and Joyner’s work on the imaging or detecting the motions?

Reid:I think it had a much bigger impact than just what it did in cardiology. Nothing much came from Wild’s lab after I left. The group in Colorado was using this immersion system, people in the water tank, and had difficulty adapting it to a clinical system. The jointed arm scanner had come out. Bill Wright had worked with a group that devised this portable scanner, but it was very small in acceptance. There was not any development work going on. NIH, according to Herman, had cut back to supporting only one obstetrician in New York who was developing some special purpose equipment. The jointed arm scanners were using storage tube scopes that had very poor resolution and were basically black and white; there was not any gray scale. Ultrasound was in a very low state there. It had not gotten to the point where anybody could consider marketing it. I am surprised that people did put money into some of the early machines because nobody knew for sure whether it would do well at that point. Claude starting going to the cardiology meetings showing that it is a useful thing. He was invited to go to Colorado to show them what was going on and it really spread.

Nebeker:Was this of great clinical importance?

Reid:Yes, I think it was. The evidence I have is that the week I left to go to the University of Washington, Blue Cross okayed payment for the examination. I figured it had to be useful or they would not do that.

Nebeker:To get the chronology down, it appears you were here at the University of Pennsylvania until 1965. Is that right?

Reid:Yes.

Nebeker:Your Ph.D. was awarded in 1965.

Reid:Yes, sometime between 1965 and 1966 I went to Seattle. My wife says we did not get there until 1966. I thought we went there in 1965. I will have to look back.

Nebeker:Did things go as you had hoped as far as completing the Ph.D. and the rest of your work here?

Reid:Yes. I figured that we needed to look at the blood flow to do much in the heart. We were looking at gross tissue motion, and if the valve is fused together so it can’t move you can see that, and that is stenosis. If it is very flexible and has a small hole and is leaking, you will not see it by motion. In the meantime Rushmer’s group had developed a Doppler flow meter that let you look at blood flow. I knew that this was the sort of thing was going to be necessary in the future.

Nebeker:So it was the belief that being able to detect or image blood flow was clinically important?

Reid:Yes. That was, to my mind, the next step.

Nebeker:Was it clear that Doppler imaging was the way to go?

Reid:No, there was not any Doppler imaging. They were using CW Doppler that didn’t have range discrimination at all. The first step would be to make a pulse Doppler. The military pulse Dopplers all work with range ambiguities. They were not what we needed. We needed one that did not have either range or velocity ambiguities because the long time that you are stuck with either PRF, or these are too low or too fast. I do not recall if I really figured out exactly how a pulse Doppler would work. When I got to the University of Washington, Don Baker, the engineer who had worked with Rushmer the longest was still there; the original guy was gone. Baker had a block diagram of how to make a pulse Doppler by putting a lot of gates on a CW Doppler to make it like a pulse echo machine. That was sort of the catalyst. We sat down together with that thing and figured out that some of the gates were redundant and we needed to lock things together with the PRF, and we worked out the pulse Doppler.

Nebeker:Could I ask about the nature of that position at Washington?

Reid:It was a research faculty, a research assistant professor. At Penn I had been an instructor. It was sort of an all-purpose grade they had between the faculty and the graduate students. They could pay me enough so my wife still did not have to work. At the University of Washington I had a faculty appointment in the Department of Physiology and Biophysics. They did not get their bioengineering program going until later, after I had been there for a couple of years.

Nebeker:What school was that in?

Reid:I was in the medical school. Back in a medical school, in a way. You can learn an awful lot of the practical side of bioengineering inside a medical school. It started with surgery. Wild and I would go to the surgery department at six o’clock in the morning and they would review the cases. Wild would translate the medical terms and I would be able to ask questions afterwards. We would hear about operations for cancer and everything else. When I got to Penn I talked to cardiologists. I really did not get into their seminars until later. When I got to the University of Washington, I went to the radiologists meetings where they would show x-rays and some of the early CAT scans. They held them at noon so they were a lot easier to go to.

Nebeker:It was invaluable?

Reid:Absolutely. They would put up the ultrasound and x-ray and explain what they could see in one and then the other, what the result was with the patient, what kinds of treatments were available, and what was and wasn’t important.

Nebeker:At the time you moved out there, were ultrasound scans available then?

Reid:Yes. By that time the Physionics jointed arm scanner was out. Smith Kline had built the Echoline 20, which was a cardiology machine, and that was being used in cardiology. I did some small projects with a number of people out there, Murray and Bor, using the existing equipment while we worked on various other things. Don Baker and his crew were engineering and reengineering the pulse Doppler so often I figured I would work on phase tracking to look at motions you could not see in the images and what is now called tissue Doppler. That is what I did some of the original work on. I helped them out when they got into difficulty. I remember getting them to use a sample-and-hold circuit to get rid of the PRF notes that they had. They had not heard of that. That came straight from one of my textbooks at Penn to their equipment and was really critical in making it work.

Nebeker:You were in Seattle for quite a few years.

Reid:First at the University. Then they formed a bioengineering program. Curtis Johnson worked on optics. Don Baker and I put in funds for a big program project that eventually got funded. I supposedly had a million dollars to work with. Rushmer thought I should leave because I would be better off as an independent. I had been working with Merrill Spencer on trying to detect flow in the internal carotid artery. For ten years the people doing vascular diagnosis on the brain thought you could not use ultrasound to see the flow on the internal, which feeds the brain separate from the external which feeds the face.

Nebeker:Are they very close together?

Reid:Reasonably close together. They were getting branches of it over the eye and they were trying to go in through the back of the mouth to get it that way. I built Spencer a focusing transducer to try to make the determination a little easier by just using a CW Doppler, that is quite simple to use, you do not have to search the volume in three dimensions like you do with the pulse Doppler.

A lot of things came together at one point there. The group at the University of Washington was using the pulse Doppler. We were all looking at the carotid arteries, and I just saw an x-ray that showed a nice separation to a plane projection from the side. You can see the internal walls on top and the external walls on the bottom. Maybe it is backwards. I have some of the pictures. I said, “Let’s just use the CW Doppler and scan in the same direction that the x-ray does and make an image like an arteriogram without contrast materials. We can see both vessels that way.” So again we hooked up using some wood from my basement and some bead chain and a couple of potentiometers to vary the position of the spot on the storage scope. I built a two dimension scanning apparatus. You had to manually move the transducer around, and the spot followed and it painted in where the flow was. Then you could tell which vessel was which. You could put the spot in the vessel and put the headphones on and listen to the Doppler flow.

Reid:Memory being the first to go, I do not remember so much about it. I do remember going with Spencer. He had lost some medical political battle at the hospital that he had been connected with. He had been doing air embolism detection in divers with ultrasound as well as the internal carotid stuff I had been helping him with. He had left his hospital and had arranged to go to Providence Hospital in Seattle. He was overjoyed when I showed up and said, “Do you have any lab space?” The hospital was overjoyed to get an NIH grant, and they gave us an old house.

Nebeker:That was back to when you were at this Providence Medical Center division?

Reid:Yes. I was back to my old habits. First you build a lab and put some more benches together and collect equipment and get the project going.

Nebeker:Can you summarize the work you did there?

Reid:It was a vascular diagnosis in all its forms. How do you detect stenosis? How do you grade the stenosis? It was there that I sat in on their heart center meetings that were held in the evenings. They got surgeons, cardiologists, and radiologist together to discuss patients and what should be done with them. Sometimes it turned out the surgeon had already operated before they held the vote on whether they should operate or not. That is the way surgeons are.

Nebeker:This was pulse Doppler imaging blood flow?

Reid:No. We were using the old fashioned continuous wave Doppler. Gene Strandness’s group at the University was trying to use the pulse Doppler, but they had this problem of searching in three dimensions. It turned out that there were really three groups because Strandness had so much difficulty working with the bioengineering group at the University of Washington that he got his own physics guy to build him a system. Frank Barber was working at the U on their system, and I had been using the CW with Spencer on patients. We had done dozens of patients but less than 100. Strandness had eight. The other group had not really been looking at patients yet.

For quite a while the Institute, near a part of Providence, survived. We manufactured some of those scanners in our lab. That was very good because the guys had to learn how to solder. Graduate students these days do not even know what soldering is.

Nebeker:Did the CW Doppler prove useful?

Reid:Yes. We sold a bunch of them. Carolina Medical Electronics made it a product and sold some. Gradually the pulse Dopplers which were much more complicated and expensive took over. To get an imaging pulse Doppler was harder. As the price came down and the availability went up, people gradually switched to the pulse Doppler. They still had a CW mode because you could use it on the heart looking at the regurgitant flow through the blood vessels, where aliasing would be a problem. Now echocardiography is a whole field. You hardly can pick up a copy of Circulation, a journal of heart research, without seeing articles on ultrasound.

Nebeker:Did you get into pulse Doppler?

Reid:Yes. We built an imaging pulse Doppler. Pulse Doppler is great for looking at a particular range where you have something. The duplex scanner that was mentioned in my publication list had only five range gates. The problem was to get a system that was continuously processed to make many range gates. That is what we very modestly called the infinite gate pulse Doppler. I did not develop it. I did work on the infinite gate system, but did not develop the digital stuff presently being used.

This was a strange thing. The University of Washington was working on a digital way of doing it. Brandistini and somebody else in Europe did the first demonstration of how you could do serial processing to derive the Doppler shift. You had to fire several times, take a sample of what I call the slow time direction at right angles to the range direction to derive the Doppler shift. You have to store the data and recycle it in and out. It gets to be quite a design problem to really make a flow image where you have a bunch of pixels, now color-coded to show the flow speed. It is called color flow imaging. They were doing a digital one. We did not have the resources to do that. But this Japanese fellow, Yasuhito Takeuchi, I met at a meeting stopped by and gave me some quartz delay lines and said you could do it through delay lines, the same way they are doing in radar by a moving target indicator at all ranges. But you have to put in fixed echo cancellers, which was the problem the early workers in Europe had run across. It worked on the bench in a water tank but it would not work in tissue. They needed fixed echo cancellers. We came out with the infinite gate pulse Doppler. The University came out with this digital system. The next thing we knew, the University’s grant had been canceled. That whole project moved to ATL, and it was years before anybody really did anything with the imaging pulse Doppler. I was tired of living on soft money at that time. I had a research appointment at the University, but there was no salary connected with that. I was raising my own salary and that of eight other people in the lab. When Drexel offered me a chair position with initial funding, it was almost too good to be true. Unfortunately, I had to go back to Philadelphia. This was my third trip to Philadelphia.

Nebeker:You can’t get away from those Philadelphia summers.

Reid:[Emphatic nod] I had to work on my thesis in the basement the second time because I did not have air conditioning at home or in the car. Your papers would stick to your hands and sweat would get in your eyes. My temper would get short. If it were not for the encouragement of my wife and children I never would have made it.

Nebeker:Were there good conditions when you came to Drexel for your work?

Reid:I made sure there would be good conditions insofar as I could. I did not know about all the academic politics that have afflicted Drexel ever since. I rented a place on the main line and I made sure I could take the train in because I did not want to drive on the Schuylkill Expressway.

Nebeker:How did your research and your work with graduate students go at the University?

Reid:Dov Jaron, the director, had warned me that working in a university was different. There would not be so many support people unless I could bring in one guy. Just when the graduate students really got good at what they were doing, they would leave. We got into digital hardware, and there I was, a complete novice. I needed graduate students who could do the programming. I had taken a programmed learning course in FORTRAN Zero--they did not even put numbers on it in those days at Penn!--I had punched a bunch of cards and cranked out some figures on transducer design. It was very different in those days.

Nebeker:Is that something that was very noticeable in your field, the coming of digital techniques?

Reid:Yes. I wanted to do a lot of processing on the signals. We were still trying to identify cancer as different from non-cancer. We were still trying to do Doppler processing, and that involved a lot of storage. We bought a DEC 11-73 and got the multi-user operating system. For personal computers we got into a deal for the Apple II Plus. A Korean company had gambled that Apple would not win a patent litigation suit they were in, and Apple did win against people building clones of the Apple system. So they had a bunch of Apple II Plus clones that they sold to Drexel for a few hundred bucks a piece. We all got them. I reconfigured mine to work as a VT100 so I could use it as a terminal. With that system you could do word-processing and stuff like that. From that point on we sort of grew up with computers. I had an 11-73 at the institute in Seattle that I left there. We had these wonderful things like hard drives that held one whole megabyte.

Nebeker:I can just imagine that it makes a big difference when you are trying to form images and discriminate with older scopes, as opposed to doing everything digitally and use algorithms afterwards to try to discriminate.

Reid:[Nodding] That really started with the Doppler systems because it was clear that Fast Fourier Transforms would be the key to making a display that would show the frequency on the scope. We had problems. Doctors that were going to interpret Doppler had to have an audiometer test. One of the associates came to pick out the bubble signals, because we were involved with NASA in Seattle, and were the astronauts going to have bubbles in their blood as the pressure decreases going out in the space walks? The divers that were doing undersea exploration were getting the bends from gas bubbles. We had quite a project going in and identifying those. I worked on that. He came and said, “These patients are not bubbling. There are no signals.” We played the tapes and there they were—his hearing cut off at the lower frequencies. So we were giving audiometer tests. Spencer, who had a lot of musical training, was able to discriminate subtle features of flow just by listening, but the other guys could not do it and I could not do it.The idea was that we needed to get fast FFTs and throw it up on the screen so you could see the short time FFTs in real time. Ron Hileman at Carolina Medical did it with digital techniques using memories and the fast multipliers, swapping the data back and forth between memories and putting it up on the screen. He came up with a commercial FFT analyzer for Doppler, and some others came out about that time. They were really embedded in our thinking. My graduate students wanted to work on various projects. It was a little difficult to get them to work on the things that I thought they should be working on. They needed some skill at acquiring the data, and this meant doing some clinical scanning on volunteers. They have since done well and brought out the K distribution for identifying scattering structures that came straight from radar but had to be adapted for ultrasound.

Nebeker:Sounds like a theme in your career—things from radar adapted.

Reid:Yes, they certainly had done a lot of useful things. I was not going to turn it down just because they had done it. Actually, it was Shankar that pointed it out to one of my graduate students. He has been working on it ever since and has his own graduate students here in this lab where the interview was happening.

Nebeker:You have a very large number of publications.

Reid:Once you get in with graduate students and they start publishing, your name goes on the end. I always put my name on the back end to indicate that I was just the guy at the tiller steering the ship and bringing in the money to pay the graduate students stipends.

Nebeker:If you were to summarize the years at Drexel, what are the things that stand out in your mind? You mentioned the the volunteer cases to scan. . .

Reid:Yes. I was getting into all kinds of different activities: looking at maximum entropy, angular frequency propagation, digital Fourier transforms, a lot of math that was being developed for imaging processing and non-Rayleigh statistics. The Wigner distribution got in there. Cepstrum techniques got lot of thinking about speckle and influence of phase and can phase be used to see things buried in speckle, which I’m still working on. I am going to get Matlab, a math program running on my computers at home. My basement is now my workspace.

Nebeker:Did you move more to the imaging processing part of this rather than the building of equipment to obtain images?

Reid:Yes, the math of signal processing, using it to derive info on the “targets.” I should mention a project that did build; a breast scanner but was outdated by computer and other advances before it got into operation. The work with Newhouse on how the Doppler bandwidth due to transit through the beam can be used to estimate speed in that direction. The Doppler effect just works along the beam, not at right angles, convolution and trying to classify scatterer structures. I had worked out methods for measuring scattering at Penn, just a straight analogy from radar. Other groups had been working in the field and were doing some more advanced ways of characterizing beams. I kept working on that and did chapters in Greenleaf’s book and in Kirk Shung’s book. Shung was a graduate student I had worked with at the University of Washington. Incidentally, the drawback at UW was that I could not have my own graduate students. Research professors were not allowed to, but coming to Drexel I did have my own graduate students and other collaborators in other laboratories.

Nebeker:Since we are very short on time, may we get into the topic of biomedical engineering and the medical profession? You mentioned that you gain a lot from being an associate at medical schools.

Reid:I never had any degree in biomedical engineering. I am an electrical engineer. I sat in on physiology classes at the University of Washington, but they were not very quantitative. They were doing their best with the biophysicist there.

Rushmer certainly had a quantitative approach.

Nebeker:Has there been a noticeable change over your career? Certainly there are a lot more biomedical engineers now, and I would imagine the medical profession is much more receptive now to working with engineers.

Reid:Yes, outside of the confusion of whether we are doing DNA analysis and that sort of thing. It has expanded so far that is hard to really define the field. For a long time I got the feeling that the biomedical engineers were system physiologists with quantitative output and they were not interested in imaging.

Nebeker:You were maybe more related to clinical work than a lot of people in the field who may have been closer to biophysics.

Reid:Yes, but it was imaging. It was making pictures. I want to mention that my last two years at Drexel I spent most of my time cheating the graduate students, maybe, but I was teaching a course to non-engineers on systems analysis. I learned quite a bit because I was trying to bring in medical and physiological models. I had some software that did compartment modeling as well as network modeling, and trying to teach these kids Fourier transforms and Laplace transforms and the difference in frequency domain and time domain, and bringing in actual physiological models which I got from the EMBS proceedings. I gave them projects to work on like the action potential using the nonlinear differential equation: build the model on the computer and use a nonlinear differential equation. By the time they got through two quarters of this they were quite sophisticated; I felt they were up to the point where they could talk to the engineers as equals. They were not at all mathematically or physically based to do the engineering work, but they were doing what I thought they were supposed to be doing. We call it biomedical science; we did not call it biomedical engineering. Then an M.D. came into the program who had his own IBM computer at home and he could work rings around the rest of us. I realized that the gap was narrowing between the medical people and the engineering people. There are people in the middle now as well as biomedical engineers. Because in the early days, the biomedical engineers that graduated from some of the programs were used as salesmen and in marketing departments.